US10590024B2 - Production method for multicore optical fiber - Google Patents

Production method for multicore optical fiber Download PDF

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Publication number
US10590024B2
US10590024B2 US15/864,028 US201815864028A US10590024B2 US 10590024 B2 US10590024 B2 US 10590024B2 US 201815864028 A US201815864028 A US 201815864028A US 10590024 B2 US10590024 B2 US 10590024B2
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cladding tube
optical fiber
common cladding
holes
multicore optical
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US20180244556A1 (en
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Takuji Nagashima
Tetsuya Nakanishi
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Sumitomo Electric Industries Ltd
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Sumitomo Electric Industries Ltd
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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
    • C03B37/01211—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments by inserting one or more rods or tubes into a tube
    • C03B37/01222—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments by inserting one or more rods or tubes into a tube for making preforms of multiple core optical fibres
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/02042—Multicore optical fibres
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
    • C03B37/01211—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments by inserting one or more rods or tubes into a tube
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
    • C03B37/01225—Means for changing or stabilising the shape, e.g. diameter, of tubes or rods in general, e.g. collapsing
    • C03B37/01228—Removal of preform material
    • C03B37/01231—Removal of preform material to form a longitudinal hole, e.g. by drilling
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
    • C03B37/01225—Means for changing or stabilising the shape, e.g. diameter, of tubes or rods in general, e.g. collapsing
    • C03B37/0124—Means for reducing the diameter of rods or tubes by drawing, e.g. for preform draw-down
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
    • C03B37/01225—Means for changing or stabilising the shape, e.g. diameter, of tubes or rods in general, e.g. collapsing
    • C03B37/01251—Reshaping the ends
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
    • C03B37/01225—Means for changing or stabilising the shape, e.g. diameter, of tubes or rods in general, e.g. collapsing
    • C03B37/0126—Means for supporting, rotating, translating the rod, tube or preform
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/02—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor
    • C03B37/025—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from reheated softened tubes, rods, fibres or filaments, e.g. drawing fibres from preforms
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/02—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor
    • C03B37/025—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from reheated softened tubes, rods, fibres or filaments, e.g. drawing fibres from preforms
    • C03B37/027—Fibres composed of different sorts of glass, e.g. glass optical fibres
    • C03B37/02736—Means for supporting, rotating or feeding the tubes, rods, fibres or filaments to be drawn, e.g. fibre draw towers, preform alignment, butt-joining preforms or dummy parts during feeding
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/02—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor
    • C03B37/025—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from reheated softened tubes, rods, fibres or filaments, e.g. drawing fibres from preforms
    • C03B37/027—Fibres composed of different sorts of glass, e.g. glass optical fibres
    • C03B37/02745—Fibres having rotational spin around the central longitudinal axis, e.g. alternating +/- spin to reduce polarisation mode dispersion
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/02—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor
    • C03B37/025—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from reheated softened tubes, rods, fibres or filaments, e.g. drawing fibres from preforms
    • C03B37/027—Fibres composed of different sorts of glass, e.g. glass optical fibres
    • C03B37/02772—Fibres composed of different sorts of glass, e.g. glass optical fibres shaping the preform lower end or bulb, e.g. pre-gobbing, controlling draw bulb shape, or preform draw start-up procedures
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2203/00—Fibre product details, e.g. structure, shape
    • C03B2203/34—Plural core other than bundles, e.g. double core
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2205/00—Fibre drawing or extruding details
    • C03B2205/06—Rotating the fibre fibre about its longitudinal axis
    • C03B2205/07—Rotating the preform about its longitudinal axis
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2205/00—Fibre drawing or extruding details
    • C03B2205/08—Sub-atmospheric pressure applied, e.g. vacuum
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2205/00—Fibre drawing or extruding details
    • C03B2205/45—Monotoring or regulating the preform neck-down region with respect to position or shape
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2205/00—Fibre drawing or extruding details
    • C03B2205/46—Monotoring or regulating the preform position with respect to the draw axis
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2205/00—Fibre drawing or extruding details
    • C03B2205/47—Shaping the preform draw bulb before or during drawing

Definitions

  • the present invention relates to a production method for a multicore optical fiber.
  • multicore optical fibers in each of which a single optical fiber includes a plurality of cores have been actively studied and reported.
  • a multicore optical fiber a plurality of cores are disposed in a common cladding made of glass in an extending direction (axial direction) of the optical fiber. Since an uncoupled-core multicore optical fiber allows communication data to be transmitted and received through cores, the amount of communication data can be increased in accordance of the number of cores.
  • a coupled-core multicore optical fiber communication data transfers between cores. However, since the communication data can be separated by signal processing on the receiving side, the amount of communication data can be increased in accordance with the number of cores.
  • An object of the present invention is to provide a method for producing a multicore optical fiber while reducing the mass of a glass block to be connected to a common cladding tube.
  • a production method for a multicore optical fiber includes in order a preform forming step, an insertion step, a heat shrinkage step, a sealing step, and a drawing step.
  • the preform forming step a common cladding tube made of quartz glass and having a plurality of holes extending in an axial direction between a first end and a second end is formed.
  • the insertion step core rods formed of quartz glass are inserted in the plurality of holes of the common cladding tube in a state in which end portions of the core rods are recessed from the first end.
  • the heat shrinkage step a diameter of the first end is reduced by heating the first end.
  • the sealing step the plurality of holes are sealed by connecting a glass block to the first end.
  • the drawing step insides of the plurality of holes in the common cladding tube are depressurized from the second end, and spinning is performed from the first end while combining the common cladding tube and the core rods.
  • a diameter-reducing step of tapering an outer peripheral portion of the common cladding tube within a fixed range from the first end to reduce a diameter of the outer peripheral portion may be included before or after the insertion step.
  • a thickness between a hole on an outermost periphery of the common cladding tube and the outer peripheral portion of the common cladding tube at the first end is preferably 10 mm or less.
  • a thickness between adjacent holes of the plurality of holes may be 10 mm or less.
  • the glass block may have a base to be connected to the first end and an apex that is smaller than the base in an area of a cross section perpendicular to an axis of the common cladding tube.
  • a mass of the glass block is preferably less than 2.63 ⁇ r 3 g when the base has a radius r cm.
  • the glass block preferably has a height h cm more than or equal to 1.15r cm.
  • the glass block may be removed from the common cladding tube by melt-drawing while keeping the holes sealed at the first end.
  • the multicore optical fiber can be produced while preventing the glass block from falling.
  • FIG. 1 illustrates a preform forming step in a production method for a multicore optical fiber according to a first embodiment of the present invention.
  • FIG. 2 illustrates an insertion step in the production method for the multicore optical fiber according to the first embodiment of the present invention.
  • FIGS. 3A and 3B illustrate a heat shrinkage step in the production method for the multicore optical fiber according to the first embodiment of the present invention.
  • FIGS. 4A and 4B illustrate a sealing step in the production method for the multicore optical fiber according to the first embodiment of the present invention.
  • FIGS. 5A and 5B illustrate a drawing step in the production method for the multicore optical fiber according to the first embodiment of the present invention.
  • FIG. 6 illustrates a preform forming step in a production method for a multicore optical fiber according to a second embodiment of the present invention.
  • FIG. 7 illustrates a diameter-reducing step in the production method for the multicore optical fiber according to the second embodiment of the present invention.
  • FIG. 8 illustrates an insertion step in the production method for the multicore optical fiber according to the second embodiment of the present invention.
  • an operation called “fiber pulling” is performed to drop a glass drop generated by heating a drawing starting end of an optical fiber preform.
  • the diameter of a glass block needed to seal a drawing starting end of the common cladding tube increases, and this also increases the mass (weight) of the glass block. For this reason, a phenomenon in which the glass block itself falls easily occurs. If the glass block itself falls, the operation is performed again. In the worst case, the operation is performed again from preparation of the common cladding tube, and this reduces the production efficiency of multicore optical fibers.
  • FIG. 1 illustrates a preform forming step in a production method for a multicore optical fiber according to a first embodiment.
  • a left part of FIG. 1 is a front view of a common cladding tube 10
  • a right part of FIG. 1 is a sectional side view of the common cladding tube 10 .
  • a common cladding tube 10 is first formed in a preform forming step.
  • the common cladding tube 10 is made of quartz glass, and has a plurality of holes 13 extending in the axial direction between a first end 11 and a second end 12 .
  • the term “axial direction” refers to a direction from the first end 11 to the second end 12 or a direction opposite therefrom.
  • the number of holes 13 is seven in the first embodiment, it may be an arbitrary natural number more than or equal to two. As a specific example of the number of holes 13 , a double-digit natural number, such as 19 or 37, can also be given.
  • the thickness of the common cladding tube 10 between the adjacent holes 13 can be, for example, 10 mm or less.
  • the thickness of the common cladding tube 10 may be the smallest between the holes 13 adjacent on the same circumference.
  • the thickness of the common cladding tube 10 may be the smallest between the holes 13 adjacent on one radius. In the former case, a distance d 1 is 10 mm or less. In the latter case, a distance d 2 is 10 mm or less.
  • FIG. 2 illustrates an insertion step in the production method for the multicore optical fiber according to the first embodiment of the present invention.
  • Core rods 14 are made of quartz glass, and the outer diameter of the core rods 14 is slightly smaller than the diameter of the holes 13 in which the core rods 14 are to be inserted.
  • the core rods 14 may be given the same outer diameter by making the diameters of the holes 13 the same. In this case, when the holes 13 and the core rods 14 are formed, trouble resulting from the difference in diameter can be reduced. Moreover, the light propagation characteristics of cores in multicore optical fibers to be produced can be made the same, and the performance of communication using the multicore optical fibers can be enhanced.
  • the core rods 14 are inserted into the holes 13 from the first end 11 of the common cladding tube 10 . Alternatively, the core rods 14 may be inserted into the holes 13 from the second end 12 .
  • FIGS. 3A and 3B illustrate a heat shrinkage step in the production method for the multicore optical fiber according to the first embodiment of the present invention.
  • the core rods 14 are inserted in the holes 13 so that end portions of the core rods 14 are recessed from the first end 11 .
  • the first end 11 is heated. That is, FIG. 3A shows that the first end 11 of the common cladding tube 10 is heated with, for example, a burner 60 in a state in which the end portions of the core rods 14 located at the first end 11 are recessed from the first end 11 to form recesses 15 .
  • FIG. 3B illustrates a state in which the diameter of the first end 11 of the common cladding tube 10 is reduced by heating the first end 11 (a left part of FIG. 3B is a front view and a right part of FIG. 3B is a sectional side view).
  • FIG. 3A when the burner 60 is placed near the first end 11 of the common cladding tube 10 , at least the outer periphery of the first end 11 is heated. By heating, the quartz glass is melted, and the surface tension acts to reduce the surface area of the melted quartz glass. A portion 16 is shrunk, and the diameter of the first end 11 is reduced, as illustrated in FIG. 3B .
  • the thickness of the common cladding tube 10 between the adjacent holes 13 is small, for example, 10 mm or less, the temperature of the material of the common cladding tube 10 between the holes 13 at the first end 11 is easily increased, and the inner diameter of the holes 13 at the first end 11 can also be easily reduced, as illustrated in FIG. 3B .
  • the core rods 14 at the first end 11 can be prevented from melting and closing the holes 13 by heating, and the holes 13 communicate between the recesses 15 to the second end 12 .
  • the recesses 15 can also be depressurized. Hence, formation of bubbles is suppressed, regardless of the presence of the recesses 15 , and the quality of the multicore optical fiber to be produced can be improved.
  • FIGS. 4A and 4B illustrate a sealing step in the production method for the multicore optical fiber according to the first embodiment of the present invention.
  • the sealing step the plural holes 13 are sealed from the side of the first end 11 by connecting a glass block 30 to the first end 11 .
  • the above-described depressurization is enabled by sealing the holes 13 .
  • a diameter d 3 of a base 31 can be made smaller than the diameter of the common cladding tube 10 in the preform forming step in accordance with the diameter of the first end 11 of the common cladding tube 10 whose diameter is reduced by the heat shrinkage step.
  • the glass block 30 preferably has, not a cylindrical shape, such a shape that the diameter decreases with an increasing distance from the common cladding tube 10 , and more preferably, has an apex 32 whose area of the cross section perpendicular to the axis of the common cladding tube 10 is smaller than that of the base 31 . Since the glass block 30 has the apex 32 , the mass of the glass block 30 can be reduced. A side surface of the glass block 30 between the base 31 and the apex 32 is concaved toward the inside of the glass block 30 , when viewed from the outside of the glass block 30 . In other words, it is preferable that the glass block 30 should be included inside a cone defined by the apex 32 and the base 31 . By using such a shape of the glass block 30 , the mass of the glass block 30 can be reduced further.
  • the preferred range of the distance between the base 31 and the apex 32 of the glass block 30 has a lower limit value in proportion to the radius of the base 31 .
  • the value 2.2 represents the glass density (unit: g/cm 3 ).
  • the mass M (unit: g) of the glass block 30 is preferably less than 2.63 ⁇ r 3 . This can more reliably form a glass drop while reducing the mass of the glass block 30 .
  • FIG. 4B is a sectional side view illustrating a state in which a handling tube 40 is connected to the second end 12 .
  • the thickness of a side wall of the handling tube 40 can be, for example, a thickness between the holes 13 on the outermost periphery of the common cladding tube 10 and the outer peripheral portion of the common cladding tube 10 .
  • the side wall of the handling tube 40 does not close all of the holes 13 , and the insides of the holes 13 can be depressurized through the handling tube 40 .
  • Connection of the handling tube 40 to the second end 12 may be performed before the insertion step.
  • an example of an upper limit value of the thickness of the side wall of the handling tube 40 is the sum of the diameter of the holes 13 and the thickness between the holes 13 on the outermost periphery of the common cladding tube 10 and the outer peripheral portion of the common cladding tube 10 .
  • FIGS. 5A and 5B illustrate a drawing step in the production method for the multicore optical fiber according to the first embodiment of the present invention.
  • FIG. 5A illustrates a state in which the common cladding tube 10 to which the handling tube 40 is connected is placed in an upright position with the glass block 30 facing down, the insides of the holes 13 in which the core rods 14 are inserted are depressurized from the handling tube 40 , and the first end 11 of the common cladding tube 10 and the glass block 30 are put in a heating furnace 50 .
  • the glass block 30 is heated by the heating furnace 50 , and a glass drop is formed and falls. Accordingly, in the drawing step, fiber pulling is performed by using a glass string continuing from the falling glass drop. After that, spinning is performed while combining the common cladding tube 10 and the core rods 14 from the first end 11 , so that a multicore optical fiber is produced.
  • the first end 11 of the common cladding tube 10 and the glass block 30 are put in the heating furnace 50 , and are melted thereby.
  • the melted glass block 30 and first end 11 can be melt-drawn downward while keeping the holes 13 at the first end 11 sealed with the glass block 30 .
  • a lump portion 33 of the melt-drawn glass block 30 may be removed.
  • the glass block 30 spun from the beginning of fiber pulling can be removed or the mass of the glass block 30 can be reduced. This can shorten the time required until spinning of the multicore optical fiber starts.
  • the diameter of the first end 11 of the common cladding tube 10 can be reduced by introducing the heat shrinkage step.
  • the mass of the glass block 30 can be reduced by reducing the size of the base 31 of the glass block 30 that seals the first end 11 . Reduction of the mass can prevent falling of the glass block 30 , and deterioration of the production efficiency of the multicore optical fiber can be suppressed.
  • FIG. 6 illustrates a preform forming step in a production method for a multicore optical fiber according to a second embodiment, and is a sectional side view of a common cladding tube 10 .
  • a common cladding tube 10 is first formed in a preform forming step.
  • the common cladding tube 10 is made of quartz glass, and has a plurality of holes 13 extending in the axial direction between a first end 11 and a second end 12 . While the total number of holes 13 provided inside the common cladding tube 10 is also seven in the second embodiment, it may be an arbitrary natural number of two or more.
  • the thickness of the common cladding tube 10 between the adjacent holes 13 can be, for example, 10 mm or less, similarly to the first embodiment.
  • inner wall surfaces of the holes 13 are subjected to gas-phase etching, and the insides of the holes 13 are cleaned by a cleaning process that heats the common cladding tube 10 while passing a cleaning gas of chlorine or oxygen through the holes 13 . This point is also similar to that of the first embodiment.
  • FIG. 7 illustrates a state in which a part of an outer peripheral portion 16 of the common cladding tube 10 within a fixed range from the first end 11 is tapered and reduced in diameter by a diameter-reducing step after the preform forming step.
  • Diameter reduction can be performed by either a mechanical method or a chemical method. Since a thickness d 4 of the outer peripheral portion 16 at the first end 11 can be reduced by the diameter-reducing step, the diameter at the first end 11 can be made even smaller than that of the first embodiment by a heat shrinkage step to be performed later. Therefore, the diameter of a base of a glass block 30 and the mass of the glass block 30 can be further reduced.
  • the thickness d 4 of the common cladding tube 10 on the outermost periphery at the first end 11 is preferably 10 mm or less.
  • the thickness 10 mm or less By making the thickness 10 mm or less, reduction of the diameter of the first end 11 in the later heat shrinkage step can be increased. This can further reduce the size and mass of a glass block to be connected to the common cladding tube 10 .
  • FIG. 8 illustrates an insertion step in which core rods 14 are inserted in the plural holes 13 after the diameter-reducing step.
  • the core rods 14 are made of quartz glass, and the outer diameter of the core rods 14 is slightly smaller than the diameter of the holes 13 in which the core rods 14 are to be inserted.
  • the core rods 14 are inserted in the holes 13 from the first end 11 of the common cladding tube 10 .
  • the core rods 14 may be inserted in the holes 13 from the second end 12 . While the diameter-reducing step is performed before the insertion step in the second embodiment, it can be performed after the insertion step, as required.
  • a heat shrinkage step and a sealing step are carried out, and a handling tube 40 is connected to the first end 11 of the common cladding tube 10 .
  • the common cladding tube 10 is placed in an upright position with a glass block 30 facing down, the insides of the holes 13 in which the core rods 14 are inserted through the handling tube 40 are depressurized, and the first end 11 of the common cladding tube 10 and the glass block 30 are put into a heating furnace 50 .
  • Spinning is performed while combining the common cladding tube 10 and the core rods 14 from the side of the first end 11 in a drawing step, so that a multicore optical fiber is produced.
  • the diameter-reducing step is introduced, the diameter of the first end 11 of the common cladding tube 10 can be further reduced. For this reason, falling of the glass block 30 that seals the first end 11 can be prevented by reducing the mass of the glass block 30 , and this can suppress deterioration of the production efficiency of the multicore optical fiber.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Dispersion Chemistry (AREA)
  • Manufacture, Treatment Of Glass Fibers (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
US15/864,028 2017-02-28 2018-01-08 Production method for multicore optical fiber Active 2038-10-04 US10590024B2 (en)

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JP7068945B2 (ja) * 2017-08-09 2022-05-17 株式会社フジクラ 光ファイバ母材の製造方法、光ファイバ母材、光ファイバの製造方法
JP7024546B2 (ja) 2018-03-27 2022-02-24 住友電気工業株式会社 マルチコア光ファイバの製造方法
JP7400585B2 (ja) 2020-03-30 2023-12-19 住友電気工業株式会社 マルチコアファイバの母材の製造方法及びマルチコアファイバの製造方法
CN112851111B (zh) * 2021-01-14 2023-04-28 艾菲博(宁波)光电科技有限责任公司 一种低串扰多芯微结构成像光纤束的制备方法

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